Dual Derailleur Hangers?

[Nvreloader]

Please help me understand Why?
I am attempting to find out why the Shimano Alivio long cage derailleur - 9 spd, would have a second hanger (1" long c/c between holes) permanently attached to it and then be attached to a standard 386 hanger, that is attached to the bike, for use with a 34T cassette, on a Jugg 4 bike?
This doesn't make sense, as the Wart Hog with a 34T (Sram) cassette, 9 speed, med length cage and is attached to the bike with no hanger, and works perfectly.

The only thing I can come up with is too drop the derailleur down for longer length/adjustment on the Jugg 4 bike?

Your thoughts and suggestions.......
Tia,

 

[Chalo]

They put the derailleur pivot where they want to, to have the geometry they choose. If that's not concentric to the thread on a standard hanger, then the derayray will feature a hanger-like appendage.

 

[lnanek]

Max low sprocket is 36T, apparently:

SHIMANO ALIVIO Rear Derailleur SHIMANO SHADOW RD 9-speed | SHIMANO BIKE-EU

The SHIMANO ALIVIO M3100 rear derailleur delivers a low profile design that lets you ride aggressively with fewer interruptions thanks to its SHIMANO SHADOW design.

bike.shimano.com

So maybe 34T was pretty close to max and not shifting smoothly under power? Could be cheaper than shift sensors to stop the mid drive if it lets them get away without those.

I've added a goat link before not just to have a bigger granny gear, but also so I could sneak more washers into each hole to get a chainline where I want side to side too.

 

[Nvreloader]

Chalo, Thank you.
I have been attempting to to get a Sram 9 sp med cage derailleur to work on this Juggs bike,
shifts and works OK. ( the Sram is a back up, for when I damage the OEM one).

Both the Alivio and Sram have the same cassette sizes, same spacing between the gears, same 34 tooth counts etc. (The Alivio long cage derailleur broke at the top wheel housing, 46.1 miles total). The Alivio shifter has the same movement measurements as the Sram 9 spd shifter.

The Sram works, but I can only get 7 speeds out of the 9 spds available, either the top 7 gears or the bottom 7 gears with the 9 spd Sram derailleur, regardless of how it is adjusted, has very smooth shifting and quite etc.

Would the second hanger cause this problem?

Should I go to a long cage Sram for this Jugg 4 bike?

So far, I have not been able to find the same hanger as used on the Shimano derailleur.
Your thoughts and suggestions,

 

[Chalo]

I have been attempting to to get a Sram 9 sp med cage derailleur to work on this Juggs bike,
shifts and works OK. ( the Sram is a back up, for when I damage the OEM one).

SRAM derailleurs have a proprietary pull ratio (between cable pull and derailleur traverse) that doesn't correspond to Shimano 5-6-7-8-9 speed or any of the several different later Shimano pull ratios.

If you want to use a SRAM shifter, you'll most likely need a SRAM derailleur. Their trade names for their SRAM-only pull ratio include "ESP" and "1:1", so if any component says that, it's trapped in SRAM land.

 

[bengxe]

Art's Cyclery Blog » Science Behind the Magic | Drivetrain Compatibility

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You just need to find a cable pull length x shift ratio that equals the sprocket pitch of your cassette.